Cytokine-based therapy has shown considerable promise in melanoma, producing high-quality responses and freedom from relapse in some patients with Stage IV or high-risk Stage III disease. Interferon alpha, FDA approved in 1996, is able to prevent relapse in up to 1/3 of patients with high-risk melanoma, with high-dose IL-2, FDA approval in 1998, produces durable responses in a 6-10% of patients with distant metastases. Efforts to improve upon these approaches have to date been unsuccessful. Perhaps the most promising approach involves combinations of IL-2 and IFN with chemotherapy, so called biochemotherapy. We developed a concurrent biochemotherapy regimen (cisplatin, vinblastine, DTIC, IL-2 and IFN) that produces tumor responses in about 45-50% of patients with metastatic melanoma and is sufficiently tolerable and practical to allow for testing in a Cooperative Group setting. This regimen in currently being explored in two large phase II Intergroup trials: a) E3695 that compares the concurrent biochemotherapy regimen with CVD chemotherapy in patients with Stage IV disease and b) SOOO8 that compares 3 cycles of biochemotherapy to a year of the standard high dose IFN in patients with stage III disease. In this project, patients treated on these two trials, as well those treated at DF/HCC institutions on similar treatments, will be asked to provide serial samples of blood, tumor and lymph node tissue. This material will be analyzed in a variety of ways to determine the mechanisms of responses and resistance to cytokine-based and cytotoxic therapy. Evidence of generation of specific immunity directed against melanoma antigens will be assessed using tetramer and ELISPOT analyses against defined melanoma peptide antigens and autologous tumor cells. Results will then by correlated with tumor response, therapy and disease status. The memory and homing properties of tetramer reactive cells will be explored using multi-parameter flow cytometry in order to determine the characteristics of T cells that best correlate with long acting immunity to melanoma antigens. In addition, T cell receptor signaling properties of peripheral blood T cells will be examined for evidence of tumor based immune dysfunction and the results correlated with treatment, disease status, and effects of therapy. Finally, melanoma tissues will be examined for the presence of various recently discovered factors associated with resistance to apoptosis (STAT1 and 2, STAT 3, Flip, Apaf-1 etc) and the findings will be correlated with treatment, treatment results and disease status. Taken together, this ambitious evaluation, should fully define the capabilities and limitations of existing therapies for advanced melanoma and, as such, will pave the way for the application of new treatments, perhaps in combination with the most promising of these standard approaches.